A toxic cleanup paved the way for Downey Studios. But people who worked on films there say they developed conditions from which they have not recovered. The source of their problems remains a mystery.

In 34 years as a Hollywood prop maker, John Izumi rarely missed a day of work. Now he can barely pull himself out of bed.

His medical records describe a daunting array of ailments: chest pains, headaches, dizziness, memory loss, red blotches and pimple-like bumps. He says he has trouble breathing at night and wakes up with tremors.

Izumi traces these symptoms to the three months he spent at Downey Studios in 2004 and 2005 building sets for the science-fiction movie "The Island."

"It's like my body is breaking down," said the 55-year-old Burbank resident. "My life has changed ever since I worked out there."

Dozens of film production workers have similar complaints about Downey Studios, which occupies the site of a former NASA plant southeast of Los Angeles that produced spacecraft for the Apollo moon missions.

Part of the property was turned into a film production center early in this decade, after a cleanup intended to protect workers and the public from the toxic residue of years of aerospace research and manufacturing. The transformation was celebrated as an example of how old industrial sites, often a burden on communities, can be reclaimed for productive uses.

But carpenters, welders, electricians and other film production workers say they developed severe respiratory and other problems while working there and have never recovered.

Film workers have given the name "Downey flu" to one particular cluster of symptoms -- chronic congestion, headaches and rashes. Some have even refused to work there, a rare phenomenon in the tough, blue-collar world of set construction.

At least 34 people have filed workers' compensation claims over illnesses they trace to the studio complex. The Times obtained detailed records on 18 of the cases. In 11 -- including Izumi's -- independent physicians found that some or all of the symptoms were caused or aggravated by working at Downey Studios.

In three other cases, independent physicians -- specialists certified by the state to offer neutral opinions in workers' compensation cases -- said the ailments appeared to be work-related but further tests were needed to make a determination. The tests were never performed because insurance companies contested the doctors' findings and refused to pay for the tests.

In the four remaining cases, independent physicians said workers' symptoms were not work-related.

The source of the health problems is a mystery. Independent physicians generally do not try to pinpoint the precise cause of an illness. In their workers' compensation claims, in injury complaints reported to Cal/OSHA and in a civil lawsuit, film-production workers cited a variety of potential causes, including mold, dust churned up during renovations at Downey Studios and toxic chemicals detected in the soil.

Stuart Lichter, whose Industrial Realty Group operates Downey Studios, rejected the idea that conditions at the site made anyone sick.

"We've done an amazing amount to transform this property, and everything we've done has been totally responsible," said Lichter, founder and president of IRG.

David White, a lawyer for the company, said there was no evidence linking the workers' health problems to Downey. "A lot of these guys work with fairly toxic materials in their line of work," he said. "They've done all kinds of heavy, industrial work."

Gerald Caton, Downey city manager, vigorously defended the cleanup of the former NASA plant: "There's probably not a site in America that has been more thoroughly evaluated from an environmental point of view."

Film production workers typically are independent contractors hired through Hollywood craft unions. While working on a movie, they are employed by payroll services companies, which purchase insurance to cover work-related injuries and illnesses.

Those insurers rejected all the claims related to Downey Studios, saying the workers' problems stem from preexisting conditions or previous employment. Workers appealed within the state workers' compensation system, and insurance carriers have since settled about a third of the cases. In a few others, claimants tired of the battle and walked away with nothing.

At least 16 workers are still fighting for workers' compensation benefits. Ultimately, disputed cases are resolved through a trial before an administrative law judge, often several years after the claim was filed.

Most of the workers who blame their medical problems on Downey have continued to work on movie productions across Los Angeles, but some have stopped, saying they are too sick.

American International Group Inc., the workers' compensation insurer in most of the Downey Studios cases, declined to comment.

"What is clear is that there is a large number of people who have reported similar symptoms from working at the same location," said Saro K. Kerkonian, a Glendale lawyer representing eight of the workers. "That can't be brushed off as just coincidence."